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SIGMON'S SEPTIC TANK SITE
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AMENDED RECORD OF DECISION OPERABLE UNIT 1 (SOILS) SIGMON'S SEPTIC TANK SITE STATESVILLE, IREDELL COUNTY, NORTH CAROLINA U.S. ENVIRONMENTAL PROTECTION AGENCY REGION 4 ATLANTA, GEORGIA August 2009
Transcript of SIGMON'S SEPTIC TANK SITE
AMENDED RECORD OF DECISION OPERABLE UNIT 1 (SOILS)
SIGMON'S SEPTIC TANK SITE STATESVILLE, IREDELL COUNTY, NORTH CAROLINA
U.S. ENVIRONMENTAL PROTECTION AGENCY REGION 4
ATLANTA, GEORGIA
August 2009
TABLE OF CONTENTS
Section Page
THE DECLARATION i
DECISION SUMMARY 1
1.0 INTRODUCTION 1 1.1 Site Location 1 1.2 Affected Population 1 1.3 Adjacent Land Uses 1 1.4 Natural Resources 2 1.5 Site Operational History 2 1.6 Highlights of Community Participation 4
2.0 REASONS FOR ISSUING THE ROD AMENDMENT 5 2.1 Description of Original Selected Remedy 5 2.2 Rationale for Changing New Selected Remedy 5
3.0 DESCRIPTION OF REMEDY CHANGES 11
4.0 STATUTORY DETERMINATIONS 13
List of Figures
Figure 1 Site Location Map 1 Figure 2 Site Layout Map 1 Figure 3 Estimated Extent of Contamination Stockpile 5 Figure 4 Photograph of Stockpile 6
List of Tables
Table 1 - Description of Remedy Changes
APPENDICES
Appendix A - North Carolina Division of Superfund Letter of Concurrence Appendix B - Addendum to the Baseline Human Health Risk Assessment
for Operable Unit 1 - Vanadium in Soil and Human Health Risk Evaluation for Arsenic and CPAHs in the Stockpile
Appendix C - Summary of Cost Estimate for Stockpile
AMENDED RECORD OF DECISION
THE DECLARATION
Site Name and Location
The Sigmon's Septic Tank Superfund site (the "Site") is located at 1268 Eufola Road in Statesville, Iredell County, North Carolina. This location is considered to be a rural area of Iredell, North Carolina. The United States Environmental Protection Agency's (EPA) Identification Number is NCD062555792. The lead agency for the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) regulatory response at the site is EPA. The North Carolina Department of Environment and Natural Resources (NCDENR) is the support agency. The site was placed on the National Priorities List (NPL) on April 27, 2005. The approximate location of the Site is shown on Figure 1.
Statement of Basis and Purpose
A Record of Decision (ROD) Amendment is needed for the Operable Unit (OU) 1 for the Sigmon's Septic Tank Site in order to modify the ROD signed on September 19, 2006. Operable Unit 1 includes soil and a stockpile of soil excavated from onsite lagoons. The Selected Remedy for the soils (including the stockpile) in the 2006 ROD was Excavation, Off-Site Transportation, and Disposal at a Subtitle D Landfill. This amendment to the ROD changes the COCs for soils and reduces the scope of the soil remedy to include only the stockpile.
In 2006, the final Baseline Human Health Risk Assessment (BHHRA) prepared for 0U1 determined that vanadium was the contaminant of concern (COC) in soil. Concentrations of vanadium were found in both surface and subsurface soils above 73 milligrams per kilogram (mg/kg), the risk-based cleanup levels for the child resident at a hazard index (HI) of 1. In May 2009, a BHHRA Addendum was prepared for OU 1 to address an update to the toxicity value for vanadium. The BHHRA Addendum provided a revised cleanup level for vanadium in soil. In addition, soil analysis conducted in April 2009, at the Site indicates the presence of vanadium is naturally occurring. Based on this new information, site-specific characterization data indicates vanadium in the soils does not pose an unacceptable risk to human health or the environment.
Additional samples were collected from the stockpile located in the southern portion of the site. In June 2009, a human health risk assessment was conducted for the additional samples collected from the stockpile. The results ofthe evaluation indicate that remedial action is warranted for arsenic and benzo (a) pyrene in the stockpile. This change to the original Selected Remedy was chosen in accordance with CERCLA, as amended, and to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP).
The State of North Carolina concurs with this amendment to the ROD (See concurrence letter Appendix A).
Rational For Amending the Scope of Work for Soils
Historical records indicated that the Sigmon's Septic Tank Service (SSTS), a wholly owned subsidiary of AAA Enterprises, pumped septic tank wastes and heavy sludge from residential, commercial, and industrial customers; installed and repaired septic tanks; and provided a variety of industrial waste removal services. From 1978 to 1992, SSTS disposed of septic wastes in eight to ten unlined lagoons on the south section of the 15-acre property. The waste was described as septage, grease, and milky white liquid. The lagoon area dimensions (encompassing all the lagoons) are 213 feet by 250 feet, or approximately 1.2 acres. In 1995, the septage and underlying soil from these lagoons were excavated and placed into a stockpile (see Figure 4).
A remedial Investigation (Rl) was conducted at the site from October 2002 through February 2005. Results from the Rl indicated that vanadium was found to be a COC for human health receptors (e.g., the child resident and the construction worker). Vanadium was found at concentrations above 73 milligrams per kilogram (mg/kg), the site-specific risk-based cleanup levels concentration for the child resident with a hazard index (HI) of 1.
EPA completed a Remedial Investigation/Feasibility Study (RI/FS) for Operable Unit One (OUI). Private wells were sampled extensively in the vicinity of the site. In April 2006, EPA conducted a time-critical removal action and installed filters on the seven residential wells. In September 2007, the Remedial Design for OUI remedy was completed and a Superfund State Contract was signed. In June 2008, EPA completed
a Remedial Investigation for groundwater (OU2). The ground water is being addressed under a separate ROD for OU 2 and is not modified by this document.
Soil samples were collected for the purpose of establishing a range of concentrations constituting background conditions for vanadium in the vicinity ofthe site in April 2009. Based on the results ofthe investigation, background has been determined to range from approximately 50 milligrams per kilogram (mg/kg) to 120 mg/kg. The average background concentration is 85 mg/kg. The background concentration results indicate that previously reported vanadium concentrations in soil are within background ranges.
In May 2009, the BHHRA Addendum prepared for OU 1 revised the cleanup level for vanadium as a result of updated toxicity values. The oral reference dose (RfD) for vanadium was updated from 1 x 10"̂ milligrams per kilogram per day (mg/kg/day) to 5 x 10"̂ mg/kg/day and the dermal RfD increased from 2.6 xlO'"* mg/kg/day to 1.3 x 10"̂ mg/kg/day. The cleanup level for vanadium in surface and subsurface soil for the child resident increased five-fold from 73 mg/kg to 365 mg/kg. As a result, none ofthe individual concentrations for vanadium in surface and subsurface soil exceeded the revised cleanup level for the child resident. Therefore, vanadium is no longer the COC in surface and subsurface soil.
In April 2009, additional samples were collected from the stockpile located in the southern portion ofthe site. The results ofthe sampling indicate that the stockpile contains concentrations that range from 52 micrograms per kilogram (pg/kg) to 642 pg/kg for benzo(a)pyrene equivalent. In June 2009, a Human Health Risk Evaluation was conducted for the additional samples collected from the stockpile. The results of the evaluation indicate that a remedial action is still warranted and needed to address arsenic and benzo (a) pyrene equivalent contamination in the stockpile. Visual observation during the sampling event also revealed evidence that some of the septage/soil material had been removed from the pile. It is possible that this material removed from the pile, which is rich in organics and nutrients, has been used by area residents as an amendment to garden soil or for other purposes, adding uncertainty to the risk evaluation. Finally, remediation ofthe stockpile will facilitate remediation ofthe groundwater at the site. The remedy for the stockpile was already selected in the ROD for OU 1, signed in September 2006, and consists of Excavation, Off-Site Transportation and Disposal at a Subtitle D Landfill.
STATUTORY DETERMINATION
Considering the new information that has been developed and the changes that have been made to the Selected Remedy, USEPA believes that the remedy remains protective of human health and the environment and complies with Federal and State requirements that were identified in the September 29, 2006 ROD, as applicable or relevant and appropriate to this remedial action at the time the original ROD was signed. Five-Year Reviews are not required for this Operable Unit.
mpp/9 Franklin E. Hill, Director Superfund Division
Date
Decision Summary
1.0 SITE NAME, LOCATION, AND DESCRIPTION
1.1 Site Location
The Sigmon's Septic Tank Site (Site) is located at 1268 Eufola Road, approximately 5 miles southwest of Statesville, Iredell County, North Carolina (Figure 1). The Site is located between Eufola Road to the north and Lauren Drive to the south. Private landowners own the properties located east and west ofthe Site; the Pine Grove Cemetery is also located east of the Site. A landing strip is located about 0.5 miles south of the Site (Figure 2).
The approximately 4,100-cubic yard stockpile is located on the southern portion (Figure 3) ofthe Sigmon Septic Tank Site property.
1.2 Affected Population
The Site is approximately 15.35 acres in size. It is divided into two properties: the southern parcel, approximately 8.9 acres and the northern parcel, approximately 6.45 acres. A family with children resides in the home onsite on the northern property. Private landowners own properties located east and west of the Site. The southern site property is bordered by a few homes on Lauren Drive to the south. Although public water is currently available, there are a number of private well users in the area. Current and future residents living onsite and offsite may be exposed to contaminants in onsite ground water. Current and future residents living offsite may be exposed to contaminants in offsite potable wells; however, during the December 2008 potable well sampling event, COCs did not exceed preliminary cleanup levels in any potable well sampled.
1.3 Land Use
Land use in the vicinity ofthe Site is residential, commercial, and industrial. The southern site property is bordered by pastureland to the east and west, and by a few homes on Lauren Drive to the south. A 1.25-acre pond south of the onsite residence is located on the northern property. Soil in the northwest corner of the pond is saturated
and a small portion was inundated up to two inches in depth. Wetland vegetation is
located in the northwest corner.
The Site is surrounded by a 4-foot barbed wire fence to the east, west, and south. However, the fence is broken in places on the east and south sides of the Site. Several trailer homes on Mustang Drive are located east of the northern site property and several residences as well as a business, Lambreth Grading, are located west ofthis property. The southern site property is bordered by pastureland to the east and west. Pine Grove Cemetery is located east ofthe Site. A landing strip is located approximately 0.5 mile south ofthe site.
1.4 Natural Resources
The ground water under the Site is designated as Class GA in accordance with North Carolina' s ground water classification system and Class IIA under EPA Groundwater Classification Guidelines (December 1986). The Class GA classification means that the ground water is an existing or potential source of drinking water supply for humans as defined in Title 15A, North Carolina Administrative Code, Subchapter 2L (T15A NCAC 2L).
EPA classifies the surficial aquifer as Class IIA since the aquifer is being used as a source of drinking water. The ground water in the bedrock aquifer is in direct contact with the surficial aquifer and is also classified as IIA. For these reasons, the ground water needs to be remediated to a level protective of pubiic health and the environment as specified in federal and state regulations governing the quality and use of drinking water. The ground water is being addressed under a separate ROD for OU 2 and is not modified by this document.
1.5 Site Operational History
SSTS, a wholly owned subsidiary of AAA Enterprises, was owned and operated by the Sigmon family since 1948. In 1970, Henry Sigmon purchased the property at 1268 Eufola Road and moved operations to this location. The business pumped septic tank wastes and heavy sludges from residential, commercial, and industrial customers; installed and repaired septic tanks; and provided a variety of industrial waste removal services. In 1980, a nephew of Henry Sigmon, Mr. Frank Sigmon, stated to North Carolina Department of Human Services that the septic service had pumped from Earnhardt, Clark Equipment, and
Union Glass. In 1996, Henry Sigmon mentioned to the NCDENR that some ofthe septic wastes came from a medical supply company, Zimmer Industries, and a metal treating business, Ro-Mac Company. Other than those sources mentioned by Mary Sigmon, no other sources of septic waste have been named in the file material.
From 1970 to 1978, the wastewaters were discharged to the City of Statesville sewer. Around 1973 or 1974, the service received permits and land applied sludges to area farmlands. The process of land application appears to have continued until at least 1989, according to septage management applications filed by AAA Enterprises. The file material does not specify on which properties the sludges were applied and whether the farmlands produced food crops. Around 1978 or 1979, the Sigmons dug several lagoons at the SSTS and began placing septic wastes into these lagoons. Henry Sigmon stated that he had received verbal permission from the Iredell County Health Department and the Mooresville Regional Office of NCDENR to construct and use the lagoons for septage disposal. No permits were ever issued for the lagoons.
A waste pile (or stockpile) and former lagoons are located in the southern portion ofthe Site (Figure 2). The structure of the stockpile consist of the pile proper, pile fingers, and the blanketed area. The pile proper is a small, relatively flat topped hill varying in height from 8 feet to 12 feet above ground level. It is more generally sloped on the north side and is nearly vertical along its southwest edge. There is a small prominent bench on the northwest side approximately 4 feet in height above ground level. The pile fingers extend off from the southwest side of the pile proper for a distance of approximately 90 feet. The height of the tops of each finger is approximately 4 feet above ground level at the southwestern terminus of each finger. The pile fingers are all rounded on top, sloping off to the level of the blanketed area around their edges. The middle finger is lobe-shaped with an irregular border. The middle finger has been recently partially excavated. The blanketed area is characterized by a thin, generally 1 to 2 foot thick layer of brown silky soil. The total volume ofthe pile proper, pile fingers, and blanketed area is approximately 4,100 cubic yards (yd^) (SESD, 2009). The Site including the resident on the property is fenced with a 4-foot barbed wire fence, and warning signs are posted on the fence and trees. There are breaks in the fence on the eastern and southern sides of the site.
The number and size of the unlined lagoons which originally existed at the site is unclear after a thorough review of the file material. Eight to ten unlined lagoons were utilized to hold septic wastes. Some references indicate the lagoons were uniform in
size while others depict lagoons differing widely in size. At times, some of the lagoons were connected with piping (referred to as a septic T) to drain water from other lagoons and facilitate the dewatering ofthe sludges. As of September 1990, eight unlined lagoons were active; six were used for septic waste and the remaining two for dewatering.
It is unknown if the lagoons ever discharged overland to the surface water pathway. Lotic (i.e., flowing) surface water features near the site consist exclusively of ephemeral drainage ditches that collect stormwater and are the discharge points for shallow ground water flow at the site. One unnamed drainage feature exists to the south of the site, and another unnamed drainage feature carries drainage from Sigmon onsite toward the west. The nearest perennial creeks or rivers are about one-half mile west and southwest of the site (i.e., Reeder Creek and the Catawba River). Uncontrolled migration of overland storm water flow may impact several small lentic (i.e., pond) surface water features in the area: Davidson Pond to the south of the site, Sigmon Pond within the site boundaries, and Lambreth and Williams Ponds to the west ofthe site. Further west of these, Sliwinski Pond lies within the drainage ditch system between the site and the Catawba River, and it could receive storm water flow originating from the site, as well.
1.6 Highlights of Community Participation
This document is based on site-related documents contained in the Administrative Record for the Site including the Remedial Investigation for OU 2 (March, 2008), Vanadium Background Study and Pile Characterization (April, 2009), Baseline Human Health Risk Assessment Addendum for Vanadium in Soil (May, 2009), and Human Health Risk Evaluation ofthe stockpile (June 2009). The Administrative Record also includes the documents used to support the 2006 ROD for OU 1.
These documents were made available to the public in both the Administrative Record and an information repository maintained at the EPA Superfund Record Center in Region 4 and at the Iredell County Public Library. In addition, over 100 copies of the Proposed Plan were mailed to citizens in neighborhoods adjacent to the site. The notice of availability of the documents was published in the Statesville Observer on June 29, 2009. A public comment period on the documents was held from July 3 to August 3, 2009.
A public meeting was held on July 9, 2009, at the Celeste Henkel School, Statesville, North Carolina. At this meeting, representatives from EPA, NCDENR, Iredell County, and major property owners answered questions about current conditions at the site and the remedial alternatives under consideration. EPA received no comments during the comment period; therefore, no Responsiveness Summary is included in this AROD.
2.0 REASONS FOR ISSUING THE ROD AMENDMENT
Based upon the consideration of the requirements of CERCLA, the NCP, and the regulatory changes at the Site, No Action (NA) is required for vanadium in surface and subsurface soils at the site. The remedy was to address soils, including the stockpiles at the site. However, as discussed previously, subsequent soil analysis indicated the presence of vanadium at concentrations at the site consistent with background concentrations found elsewhere. Also, a change in toxicity values resulted in a revised remedial goal. A review of historical activities at the site does not support a source for vanadium at the site. Forthese reasons, the ROD is being amended to drop vanadium as a COC for surface and subsurface soil at the Site.
Sampling recently conducted at the Site indicates the stockpile is contaminated with arsenic and CPAHs. Remediation ofthe stockpile is also justified by uncertainties in the risk assessment, and the fact that removal of this potential source of recontamination is expected to facilitate the remedy for groundwater (see further discussion under 2.3 below). The remedy for the stockpile was already selected in the ROD for OU 1, signed in September 2006, and consists of Excavation, Off-Site Transportation and Disposal at a Subtitle D Landfill. Based on the results ofthe 2009 human health risk evaluation, approximately 4,100 yd~̂ of stockpile will be removed. The stockpile is shown in the photograph on Figure 4.
2.1 Description of the Original Remedy
The major components of the Selected Remedy for OUI include:
• Excavation of surface and subsurface soil containing vanadium above site-specific remedial goal concentrations.
Treatment of contaminated soil that fail the Toxicity Characteristic Leaching Procedure (TCLP) to meet applicable treatment standards under 40 CFR 268 using solidification/stabilization (S/S) technologies.
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• Offsite transportation and disposal of the treated and/or untreated soil at a RCRA Subtitle D Landfill.
• Backfilling of the excavated area with clean borrow material obtained from a local source.
• Re-vegetation and restoration of site to safe and usable conditions.
Contaminated soils would be excavated, transported and disposed at a Subtitle D landfill. The excavated area will be backfilled with clean borrow material from a local source, and then the Site will be revegetated and restored to safe and usable conditions. The COCs and extent of soil to be addressed have changed based on additional sampling and revised human health risk assessment evaluations. The description of the remedy changes are presented in Table 1.
Figure 4 - Photograph of Stockpile
2.2 Summary of Addendum to the Baseline Human Health Risk Assessment for
Vanadium in Soil - OU 1
Introduction
The revised BHHRA completed in May 2009 served as an addendum to the Final BHHRA completed in March 2006, for the Sigmon's Septic Tank Superfund Site, OU 1. Revised site-specific remedial goals for vanadium in soil were calculated.
The Final BHHRA for OU 1 prepared in 2006 evaluated contamination in soil, sediment, surface water, and presented a limited ground water evaluation (Black & Veatch, 2006). Appropriate EPA guidance was used to evaluate the data, characterize potentially exposed populations, assess the toxicity of COPCs, characterize the risk, and calculate the cleanup levels. An addendum was needed to re-evaluate human health exposure to vanadium in soil at OU 1. Vanadium is considered a systemic toxicant or one that causes non-carcinogenic health effects. The oral RfD for vanadium has been recently updated from 1E-03 mg/kg/day to 5E-03 mg/kg/day and the dermal RfD changed from 2.6E-04 mg/kg/day to 1.3E-03 mg/kg/day.
Background Toxicity criteria used to evaluate potential non-carcinogenic health effects are termed reference doses, or RfDs. In developing RfDs, it is assumed that a threshold dose exists below which there is no potential for human toxicity. The term RfD was developed by the EPA to refer to the daily intake of a chemical to which an individual can be exposed without any expectation of non-carcinogenic effects (e.g., organ damage, biochemical alterations, birth defects) occurring during a given exposure period.
The toxicity values used to evaluate vanadium were obtained from the following hierarchy of sources in accordance with the EPA Office of Superfund Remediation and Technology Innovation (OSRTI) (EPA, 2003):
• Tier 1 - Integrated Risk Information System (IRIS)
• Tier 2 - Provisional Peer-Reviewed Toxicity Values (PPRTV)
o Tier 3 - Other (Peer Reviewed) Values, including: Agency for Toxic Substances Disease Registry (ATSDR) Minimal Risk Levels (MRLs); California Environmental Protection Agency values; and Health Effects Assessment Summary Tables (HEAST)
The IRIS RfD for vanadium peroxide is the basis for the evaluation of vanadium (Tier 1). The previous source of the RfD was the National Center for Environmental Assessment (NCEA) (Tier 3). The current source of the RfD for vanadium is vanadium pentoxide on IRV with an adjustment by the Regional Screening Levels (RSLs) tables (EPA, 2009), based on molecular weight. The revised Risk Assessment Guidance for Superfund (RAGS) Part D Table 5.1, which includes the updated RfD for vanadium, is included in Appendix B.
The risk of adverse non-carcinogenic effects from chemical exposure is expressed in terms of the hazard quotient (HQ). The HQ is the ratio of the daily intake (Dl) that a human receives to the RfD. The RfD is the estimated dose below which it is unlikely for even sensitive populations to experience adverse health effects. The HQ is calculated as follows:
HQ = DI/RfD
where: HQ = Hazard Quotient (unitless) Dl = Daily Intake (mg/kg/day) RfD = Reference Dose (mg/kg/day)
All of the HQ values for chemicals within each exposure pathway are summed to yield the HI. Each pathway HI within a land use scenario (i.e., future worker) is summed to yield the total HI for the receptor. If the value of the total HI is less than 1.0, it is interpreted thatthe risk of non-carcinogenic injury is low. If the total HI is greater than 1.0, it is indicative of some degree of non-carcinogenic risk, or effect, and COCs are selected.
The Final BHHRA completed in 2006 concluded that the hazards for the future construction worker and adult and child residents were above the applicable thresholds (a total HI greater 1) and the results of the addendum support those conclusions.
Risk Characterization Included in Appendix B, ofthe risk assessment addendum, are RAGS Part D Tables 7.14 RME and 7.14 RME Revised. Table 7.14 RME is the original non-cancer hazard calculation using the RfD for vanadium obtained from the EPA Region 9 PRG table (NCEA). Table 7.14 RME Revised incorporates the RfD from IRIS. The HQ for vanadium associated with incidental ingestion of soil decreased from 0.6 to 0.1; for dermal contact the HQ decreased from 0.03 to 0.01. The total HQ for vanadium exposure in surface soil decreased from to 0.6 to 0.1.
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The BHHRA completed in 2006 concluded that the total Hazard Indices for future construction worker and resident were above applicable thresholds (total HI greater than 1). The revised risk assessment, however; shows that all HI values are less than 1.
Remedial Goal Options The site-specific exposure assumptions and models were used to develop the cleanup levels for the site. As a result, the risk level for a given chemical is directly proportional to the exposure concentration. The following equation was used to calculate the chemical-specific risk-based RGOs:
Remediation Goal = TR x EC / CR where:
TR = Target Risk Level (HQ equal to 0.1, 1, and 3 for non-carcinogenic effects and risk level equal to 1E-06,1E-05, and 1E-04 for carcinogenic effects). EC = Exposure Point Concentrations in Soil CR = Calculated Risk Level.
The use of the exposure point concentration for vanadium of 47,95 mg/kg and the total HQ for vanadium calculated in this addendum results in a five-fold increase in the cleanup levels. Appendix B shows the cleanup levels for the child resident that were developed and presented in the BHHRA in 2006 and the revised cleanup levels calculated for the child resident using the updated RfD.
Conclusions The Final BHHRA prepared for OU 1 in 2006 determined that vanadium was the COC in surface and subsurface soil. Concentrations of vanadium were found in both surface and subsurface soil above the child resident HI of 1, The risk-based RGO calculated for the child resident, the most sensitive receptor was 73 mg/kg (HQ=1).
Toxicity information is subject to revision and is updated once new data becomes available. Such is the case with vanadium, where the RfD was revised upward from 1x10"^ to 5E-3 mg/kg/day. This five-fold increase has a dramatic effect on the calculated hazard and cleanup levels. The cleanup levels for soil and stockpile for the child resident exposure pathway increased from 73 mg/kg to 365 mg/kg.
It was previously determined that vanadium was the only COC in surface and subsurface soil. However, this BHHRA addendum determined that none of the individual
concentrations for vanadium in soil exceeded the revised child resident cleanup levels of 365 mg/kg. Therefore, vanadium is no longer a COC in surface and subsurface soil. The BHHRA addendum for vanadium in soil is included in Appendix B. However, since the stockpile is contaminated with arsenic and benzo (a) pyrene the 2006 remedy will still be implemented.
2.3 Summary of Human Health Risk Evaluation for the Stockpile
Data obtained from the April 2009 stockpile soil investigation conducted by the Science and Ecosystem Support Division (SESD) was screened according to EPA Region 4 policy. COPCs were identified and exposure point concentrations (EPCs) based on the maximum
detected concentration were established. Residential exposure assumptions were applied to the resultant EPCs.
According tp EPA Region 4's policy, the target total individual risk resulting from exposures at a Superfund site may range anywhere between 1 x 10'^ and 1 x IO"'*. Thus, remedial alternatives should be capable of reducing total potential carcinogenic risks to levels within this range for individual receptors.
The total estimated cancer risk for the current and future residents (3 x 10"̂ ) is within the EPA target cancer risk range of 1x10"^ to IxlO'^'with arsenic and benzo(a) pyrene being the main contributors. The total hazard index for current and future child resident is 3, which is above the EPA threshold of 1; however, individual target organ His do not exceed 1. The hazard quotients for aluminum, antimony, arsenic, iron and thallium were all greater than 0.1 but less than 1. According to EPA OSWER Directive 9355.0-30, site-specific conditions may be used to justify cleanup (EPA, 1991). The stockpile contaminated with arsenic and benzo (a) pyrene is located in the southern portion ofthe site near residential properties. Disturbance of the stockpile was observed, leading to speculation that contaminated stockpile material may have been taken off site and used in ways that add uncertainty to the risk assessment results, such as use for gardening or topsoil on residential properties. The human health risk evaluation is included as Appendix B.
Even though the cancer risks are within EPA's risk range and there is no individual
target organ specific hazard quotient greater than one, a remedial action is planned
because of site specific conditions present at the site. The stockpile was originally
excavated because ofthe contamination that was impacting groundwater and the lagoons
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contained high concentrations of metals and other contaminants. There is a large degree
of uncertainty in sampling a pile in its excavated form and it is known that this pile includes
septic waste (including biological contamination) that may or may not show up in sampling
data. Also, since groundwater levels exceed drinking water MCLs and/or risk based levels,
andthe stockpile isa likely source of contaminants, removal ofthis source should enhance
the prospects for success ofthe groundwater remedy. The soil data has been compared
with soil levels that consider leaching to groundwater. Since the soil levels for arsenic
exceed the leach-based concentrations, removal or remediation ofthe soil in the stockpile
is justified in helping to protect for health based standards in groundwater.
3.0 DESCRIPTION OF REMEDY CHANGES
Differences between the 2006 ROD and the current ROD Amendment are outlined below:
• In the 2006 ROD, soil and stockpile contaminated with vanadium above 73 mg/kg required excavation, transportation and disposal at a Subtitle D landfill. The excavated area was to be backfilled with clean borrow material from a local source, and then the Site would be revegetated and restored to safe and usable conditions. In this ROD Amendment, only the stockpile with contaminants including arsenic and PAHs will be disposed at a Subtitle D landfill.
• This ROD Amendment documents a decrease in the estimate of contaminated soil to be excavated, evaluated and, if necessary, treated and properly disposed, from 12,000 cubic yards to 4,100 cubic yards.
• This ROD Amendment documents a decrease in the estimated cost of the remedy,
from approximately $2,100,000, million to $906,000.
• The 2006 ROD estimated an excavation range of 1 to 2 feet for the soils and 1 to 7 feet for the stockpile to achieve cleanup goals. This ROD Amendment documents that that the stockpile will be removed to six inches below native grade material. Then confirmatory sampling will be conducted.
The cleanup level required for vanadium in the 2006 ROD was 73 kg/mg. In the ROD Amendment, the cleanup level for arsenic is 3-10 mg/kg and for benzo(a)pyrene equivalent is 60 ug/kg; no cleanup is required for vanadium in soil.
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TABLE 1. SUMMARY OF AMENDED RECORD OF DECISION
Volume of contaminated soil and stockpile for excavation Depth of excavation
Estimated Area to be Graded Soil and stockpile with vanadium concentrations above 73 ppm
Estimated Cost
2006 Remedy
12,000 cy
2 feet for soils and 7 feet for the stockpile
15.3 acres
Excavation, onsite treatment with solidification/stabilization, and off-site disposal of treated waste at a Subtitle D landfill
$2.1 million
Revisions in this AROD 4,100 cy
No excavation of soil other than the stockpile 6 inches below native grade materials in the stockpile footprint 1 acre
Only the stockpile with Arsenic background concentrations which range from 3 - 1 Oppm and benzo(a) pyrene equivalent above 60 ug/kg will be transported to a Subtitle D landfill
$906,000
Difference
7,900 cy
No soil excavation required beyond the stockpile
14.3 acres
Change from remediation of soils and stockpile to the removal ofthe stockpile contaminated with arsenic and benzo(a)pyrene equivalent.
$1,194,000
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4.0 STATUTORY DETERMINATIONS
Under its legal authorities, EPA's primary responsibility at Superfund sites is to select remedial actions that are protective of human health and the environment. In addition. Section 121 of CERCLA established several other statutory requirements and preferences. These specify that when complete, the selected remedial action for a site must comply with applicable or relevant and appropriate environmental standards established under Federal and State environmental laws unless a statutory waiver is granted. The selected remedy must also be cost-effective and utilize permanent treatment technologies or resource recovery technologies to the maximum extent practicable. Finally, the statute includes a preference for remedies that permanently and significantly reduce the volume, toxicity, or mobility of hazardous wastes.
Considering the new information now available and the changes been made to the selected remedy by this ROD amendment, USEPA believes that the excavation remedy will be protective of human health and the environment and complies with federal and state requirements that were identified in the September 2006 ROD as applicable or relevant and appropriate to this remedial action. In addition, the revised remedy utilizes permanent solutions and alternative treatment technologies to the maximum extent practicable for this site.
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Image Copyright 2008 Digital Globe
N o t e : "0 f t" around perimeter of pile anci associateci features indicates local ground surface. Footage indicateci inside pile and features is estimated height, above ground surface, at the indicated location.
F igure 3 Pile Mo rpho logy S igmon 's Sept ic Tank S u p e r f u n d Si te Statesv i l le , I redel l County , No r th Caro l ina
APPENDIX A
State of North Carolina Concurrence Letter
^ k NCDENR
North Carolina Department of Environment and Natural Resources Division of Waste Management
Beverly Eaves Perdue Dexter R. Matthews Dee Freeman
Governor Director Secretary
24 August 2009
Ms. Beverly Stepter Superfund Branch, Waste Management Division US EPA Region IV 61 Forsyth Street. SW Atlanta, Georgia 30303
SUBJECT: Concurrence with Amended Record of Decision Sigmon's Septic Tank Site Operable Unit 1 Statesville, Iredell County
Dear Ms. Stepter:
The State of North Carolina by and through its Department of Environment and Natural Resources, Division of Waste Management (herein after referred to as "the state"), reviewed the Amended Record of Decision (AROD) received by the Division on 24 August 2009 for the Sigmon's Septic Tank Site Operable Unit 1 Site and concurs with the selected remedy, subject to the following conditions:
1. State concurrence on the AROD for this site is based solely on the information contained in the AROD received by the State on 24 August 2009. Should the State receive new or additional information which significantly affects the conclusions or amended remedy contained in the AROD, it may modify or withdraw this concurrence with written notice to EPA Region IV.
2. State concurrence on this AROD in no way binds the State to concur in future decisions or commits the State to participate, financially or otherwise, in the clean up ofthe site. The State reserves the right to review, overview comment, and make independent assessment of all future work relating to this site.
3. If, after remediation is complete, the total residual risk level exceeds 10'^, the State may require deed recordation/restriction to document the presence of residual contamination and possibly limit future use ofthe property as specified in NCGS 130A-310.8
1646MailServiceCenter, Raleigh, North Carolina 27699-1646 N l H - V i r ^ 1" Phone: 919-508-8400 \ FAX: 919-715-4061 \ Internet: www.wastenotnc.org i N O r m C a T O i m a
An Equal Opportunity \ Affirmative Action Employer J^atumlly
The State of North Carolina appreciates the opportunity to comment on the AROD and looks forward to working with EPA on the remedy for the subject site. If you have any questions or comments, please call Mr. Nile Testerman at 919 508-8482.
Dexter R. Matthews, Director Division of Waste Management
cc: Jack Butler, Chief NC Superfund Section David LowTi, NC Superfund Nile Testerman, NC Superfund
1646 Mail Service Center, Raleigh, North Carolina 27699-1646 Phone: 919-508-8400 \ FAX: 919-7154061 \ Internet: www.wastenotnc.org
An Equal Opportunity \ Affirmative Action Employer
North Carolina i^atuvally
APPENDIX B
Addendum to the Baseline Human Health Risk Assessment for Operable Unit 1 -Vanadium in Soil
and
Human Health Risk Evaluation for Arsenic and CPAHs in the Stockpile
BLACK & VEATCH
Technical Memorandum
To: Beverly Stepter, EPA Remedial Project Manager
From: Gina Kelly Montgomery, Black & Veatch Project Manager
Re: Addendum to the Baseline Human Health Risk Assessment for Operable Unit I Re-evaluation of Vanadium in Soil - Human Health Exposure Siginon's Septic Tank Superftind Site Statesville, Iredell County, North Carolina
Date: May 15,2009
Introduction
The purpose ofthis technical memorandum is to serve as an addendum to the Final Baseline Human
Health Risk Assessment (BHHRA) completed in March 2006, for the Sigmon's Septic Tank
Superfund Site (SSTS), Operable Unit (OU) 1, located in Statesville, Iredell County, North
Carolina. This memorandum will also present revised site-specific remediation goal options
(RGOs) for vanadium in surface soil.
The Final BHHRA for SSTS OU I prepared by Black & Veatch in 2006, addressed contamination
in soil, sediment, surface water, and presented a limited ground water evaluation (Black & Veatch,
2006). Black & Veatch used appropriate United States Environmental Protection Agency (EPA)
guidance to evaluate the data, characterize potentially exposed populations, assess the toxicity of
chemicals of potential concem (COPCs), characterize the risk, and calculate the RGOs. An
addendum is needed to re-evaluate human health exposure to vanadium in surface and subsurface
soil at SSTS OU 1. Vanadium is considered a systemic toxicant or one that causes non-
carcinogenic health effects. The oral reference dose (RfD) for vanadium has been recently updated
from IE-03 milligrams per kilogram per day (mg/kg/day) to 5E-03 mg/kg/day and the demial RID
changed from 2.6E-04 mg/kg/day to 1.3E-03 mg/kg/day.
Background
Toxicity criteria used to evaluate potential non-carcinogenic health effects are termed reference
doses, or RfDs. In developing RfDs, it is assumed that a threshold dose exists below which there is
no potential for human toxicity. The term RfD was developed by the EPA to refer to the daily
Technical Memorandum EPA Conlract No.: 68-W-99-043 Work Assignment No.: 693-RICO-A44F Black & Veatch Project No. 48693.01.13
Sigmon's Septic Superfund Tank, OU 1 Revision 0 May 2009
Page 2
intake of a chemical to which an individual can be exposed without any expectation of non-
carcinogenic effects (e.g., organ damage, biochemical alterations, birth defects) occurring during a
given exposure period.
The toxicity values used to evaluate vanadium were obtained from the following hierarchy of
sources in accordance with the EPA Office of Superfund Remediation and Technology Innovation
(OSRTI) (EPA, 2003):
• Tier I - Integrated Risk Infomiation System (IRIS)
• Tier 2 - Provisional Peer-Reviewed Toxicity Values (PPRTV)
• Tier 3 - Other (Peer Reviewed) Values, including: Agency for Toxic Substances Disease
Registry (ATSDR) Minimal Risk Levels (MRLs); California Environmental Protecdon
Agency values; and Health Effects Assessment Summary Tables (HEAST)
The IRIS RfD for vanadium peroxide is the basis for the evaluation of vanadium (Tier 1). The
previous source of the RfD was the EPA National Center for Environmental Assessment (TMCEA)
(Tier 3). The current source of the RfD for vanadium is EPA IRIS adapted by the Regional
Screening Levels (RSLs) tables (Tier 3) (EPA, 2008). There is a higher level of uncertainty
associated with these sources, compared to sources considered Tier I and Tier 2 values. The
revised Risk Assessment Guidance for Superfund (RAGS) Part D Table 5.1, which includes the
updated RfD for vanadium, is included in Appendix A.
The risk of adverse non-carcinogenic effects from chemical exposure is expressed in tenns ofthe
hazard quotient (HQ). The HQ is the ratio ofthe daily intake (DI) that a human receives to the RfD,
the estimated dose below which it is unlikely for even sensitive populations to experience adverse
health effects. The HQ is calculated as follows (EPA, 1989):
HQ Dl/RfD
Wliere:
HQ
DI
RfD
Hazard Quotient (unitless)
Daily Intake (mg/kg/day)
Reference Dose (mg/kg/day)
All ofthe HQ values for chemicals within each exposure pathway are summed to yield the hazard
index (HI). Each pathway HI within a land use scenario (i.e., fiiture worker) is summed to yield the
Technical Memorandum EPA Conlract No.: 68-W-99-043 Work Assignment No.: 693-R1CO-A44F Black & Veatch Project No. 48693.01.13
Sigmon's Septic Superfund Tank, OU 1 Revision 0 May 2009
Page 3
total HI for the receptor. If the value ofthe total HI is less than 1.0, it is interpreted to mean that the
risk of non-carcinogenic injury is low. If the total HI is greater than I.O, it is indicative of some
degree of non-carcinogenic risk, or effect, and chemicals of concem (COCs) are selected (EPA,
2000).
The Final BHHRA completed in 2006 concluded that the hazards for the future construction worker
and adult and child residents were above the applicable thresholds (a total HI greater 1) and the
results ofthis addendum support those conclusions.
Risk Characterization
Included in Appendix A are RAGS Part D Tables 7.14 RME and 7.14 RME Revised. Table 7.14
RME is the original non-cancer hazard calculation using the RfD for vanadium obtained from the
EPA Region 9 PRG table. Table 7.14 RME Revised incorporates the RfD from the RSLs table. The
HQ for vanadium associated with incidental ingestion of soil went from 0.6 to O.l; for demial
contact the HQ went from 0.03 to 0.01. The total HQ for vanadium exposure in surface soil went
from to 0.6 to 0.1.
Remedial Goal Options
The site-specific exposure assumptions and models were used to develop the RGOs the site. This
leads to the risk level for a given chemical being direcfiy proportional to the exposure
concentration. The following equation was used to calculate the chemical-specific risk-based
RGOs:
Remediation Goal = TR x EC / CR
Where:
TR
EC
CR
Target Risk Level (HQ equal to 0.1, 1, and 3 for non-carcinogenic effects and
risk level equal to lE-06, I E-05, and lE-04 fbr carcinogenic effects).
Exposure Point Concentrations in Soil
Calculated Risk Level.
The use of the exposure point concentration for vanadium of 47.95 milligrams per kilogram
(mg/kg) and the total HQ for vanadium calculated in this addendum, results in a five-fold increase
in the RGOs. Table I shows the RGOs for the child resident that were developed and presented in
the BHHRA in 2006 and the revised RGOs calculated for the child resident using the updated RfD.
Technical Memorandum EPA Contract No.: 68-W-99-043 Work Assignment No.: 693-R1CO-A44F Black & Veatch Project No. 48693.01.13
Sigmon's Septic Superfund Tank, OU 1 Revision 0 May 2009
Page 4
Conclusions
The Final BHHRA prepared for SSTS OU 1 in 2006 determined that vanadium was the COC in
soil. Concentrations of vanadium were found in both onsite and off-site soils above the child
resident hazard index (HI) of 1. The risk-based RGO calculated for the child resident, the most
sensidve receptor was 73 mg/kg (HQ=1).
Toxicity information is subject to revision and is updated once new data becomes available. Such is
the case with vanadium, where the RfD was revised upward from lE-3 to 5E-3 mg/kg/day. This
five-fold increase has a dramatic effect on the calculated hazard and RGOs. The RGO for soil for
the child resident increased from 73 mg/kg to 365 mg/kg.
It was previously detennined that vanadium was the only COC in soil. However, this addendum
detemiined that none of the individual concentrations for vanadium in soil exceeded the revised
child resident RGO of 365 mg/kg. Therefore, soil is no longer a media of concem at the SSTS.
References
Black & Veatch, 2006. Black & Veatch Special Projects Corp. Final Baseline Risk .Assessment for Human Health, Sigmon 's Septic Tank Site, Iredell County, North Carolina, June.
EPA, 1989. U.S. Environmental Protection Agency, Risk Assessment Guidance for Superfund (RAGS), Volume I, Huinan Health Evaluation Manual (Part A), Interim Final, Office of Emergency and Remedial Response, Washington, DC, EPA/540/1-89/002, 1989.
EPA, 2000. U.S. Environmental Protection Agency, Supplemental to RAGS: Region 4 Bulletins Human Health Risk Assessment Bulletins, EPA Region 4 Originally Published in November 1995: http://www.epa.gov/region4/waste/oftecser/healtbul.htni, 2000.
EPA, 2003. U.S. Environmental Protection Agency, Huinan Health Toxicity Values in Superfund Risk Assessments, Office of Superfund Remediafion and Technology Innovafion, OSWER Directive 9285.7-53, December 5.
EPA, 2008. U.S. Environmental Protection Agency, Regional Screening Levels (RSLs), September 12. http://www.epa.gov/reg3hwmd/risk/hunian/rb-concentration_table/index.htm.
TABLE 1 REMEDIAL GOAL OPTION CALCULATIONS FOR SIGMON'S SEPTIC TANK OU 1 - VANADIUM IN SOU
Rcceptor/Analytc
Future Child Resident
Surface Soil 2006 Calculation
Vanadium
Exposure Point Concentration
(mg/kg)
47.95
Hazard Totals
Ingestion
0.6
2009 Revised Calculation Using Updated RfD
Vanadium 47.95 O.l
Inhalation Dermal
0.03
O.OI
To ta l
N o n C a n c e r
0.65
0.13
Hazard Quotient Level (mg/kg)
HQ=0.1
7.3
37
HQ=1
73
365
HQ=3
219
1,096
mg/kg = Milligrams per kilogram RID - Reference dose
T A B L E S . ! REVISKD
NON-CANCER T O X I C I T Y D A T A - O R A L / D E R i M A L
Sigmon's Septic Tank
Statesvilk', Iredell Countw North Carol ina
Chemical
of Potential
Concern
Vanadium
Chronic/
Suhchronic
Chronic/Siibclironic
Ora l RfD
Value
• 5R-n3/NA
Units
mg/kg-day
Ora l Absorpt ion
Efficiency for Derinal
(1)
0.26
Absorbed RfD for Dermal
(2)
Value
I.3E-03
Units
mg/kg-d,iy
Pr imary
Target
Effect
Decrenscd Cystine in H.TJr
Combined
Unccrtaint j ' /Modi fy ing
Factors
N/A
RfD:1 arget Organ(s)
Sourcc(s)
(3)
RSL
Dale(s)
( M M / D D / Y Y V V )
9/12/2U0S
N/A - Not Applicable
RSL - HPA Regional Screening Level fhllp://w\vw.epa.gov/rcg3hwmd/risk/hunian/rb-concentration_lable/indc.x,lilin)
mg/kg-day - Mill igrams per kilograms per day
(1) Refer 10 RAGS Part E (2004) und te.\i for explanation. Nole: Oral lo Dermal Adjustment Factors from I :xh ib i i4- I , RAGS Part \ i , 2004
(2) See R-^GS Part E (2004). Page 4-3. Nole: Dermal RtD (mg/kg) = Oral RlD (mg/kg) .\ Oral to Dermal Adjuslmeni Factor (3) RSL Table (values obtained dale Indicated), based on EPA IRIS,
TABLE 7.14 RME 200ft
C . \LCl iLATION OF CHEMICAL CANCER RISKS AND NON-CANCER HAZARDS
Sigmon's Sfptic Tank
St-Jtesvillc, Iredell Counly. North Carolina
Scenatin
Rec
Pec
tplO
cpio
Tiiriirrramc:
Pop
.^yc
b [ on:
'h i ld
C
Rc
rrr ni/Future
-idem
Medium
Soil/Dr>'Sfdimeni
Kiposure
Medium
Soi lDr.-Sedimem
t.iposuie Medium
Kxposure Poini
lace Suil'Dr>'Sedin
h\posure
Route
InyeMiun
ii.\p Rome Total
Dermal
E\p. Route Total
Chemieal o f
Poieniial Concem
Aluminum
.Arsenic
Chiomiimi
Iron
Manganese
Vanadium
2. . ' .7 .3-TCDDTt(
KPC
Value
:n54 ' i
: 0
in.m
1931.7
: m
J7.15
0.0000071
Units
nis/kg
nifc '̂kB
mw,'kB
mu'kg
mg'kg
mg/kg
m t ' k g
Aluminum
,\rsenic
Chromium
Iron
Manganese
Vanadium
;.3,7.S-TCDDTl-; i
w j q
2.(1
20.(14
193tj7
210
47.95
f>.0f")0(i7l
mg'kv;
mg'kg
mg'kl!
mg'Vg
mg'kg
mg/kg
mg/kg
K.Tpoiurc Poini T o u i
T>.ul
Soi l /Drv Sediment T t i t i l
SuifLice V«.'aier Surlace Waiei
Kvposuie Medium
JnienTiiilem Sneam Ingestion
Hvp. Route Taial
Aisenic
l ion
Manyanese
Vanadium
0.00004
22
1.2
0 0051
mg/L
mg/L
mg/L
mg'L
Exposure Puiiil Tolal
Total
Surface \Va(er Tota l
Groundwater Groundwaler Groundwater
Tap Water
Ingestion 1.4-Dichlorobenze
Benzene
Chloroform
Tr ich lorct f ih fnc iT
2-Meth>lnaphlhale
Naphthalene
Aldr in
atpha-BlIC
beta-BHC
Heptachlor
,Mummum
0.0074
0,00)179
0.00044
0 00024
0 001171
0.00 U
0,00003
0,00Ui)2K
O,OO0(tSR
<} ()OO03l5
9.579
mg/L
mg'L
mg/L
mg/L
mg/L
mi j 'L
mg/L
mg'L
mg'L
mg'L
mg/L
Intake/b'Tpoiur
Value
2.31^-002
2.2H-O0h
2.2K-I105
; 1K o n :
2.3K-004
5.3H-On5
7.SB-012
C
e Concentralion
Units
mg/ku'day
m g k t ' d a y
m t^k t ' d . y
mg'kg/Jay
mg'kg.'day
mg/kg/day
mg/kg/day
ncerRi ik CalcuUii
CFS/U
Value
NA
1.5H^ 000
NA
NA
NA
NA
1.5E+005
na
„ i ,R i , .
Units
1/mg'kg/day
1/mg'kg'day
l/'tiig'kg'day
l/mg'kg/day
1 /mg/kg/'day
l/mg'kg/day
i/mg'kg/day
. ( . l f -n04
1.(Jl--n(i^
3 ()h-007
2.IK-004
3 . : K - 0 0 I I
7.2K-007
1,1H-013
nig'kg'da>
niiukg'da>
mg'kg'day
mg'kg'day
mg't:g/day
mg'Vg'djy
mg'kg'day
NA
1 4E'Oi.iO
NA
NA
NA
NA
1.5 K1005
1/mg'kg'day
1/mg'kg'day
l/mg'kg/'iiay
1/mg'kg'day
1/mykg/day
1/mg/kg/day
1/mg/kg'day
7.1t-008
1.7B-00J
•̂ .OH-OOS
3.SK.007
mg'kg/day
mg/kg/day
mg-kg/day
mg'kg/day
I.5E4000
NA
NA
NA
1/mg/kg/day
1/mg/kg'day
l/mg'kg/day
1/mg/kg/day
4. IE-005
4.3K-O0h
2.7H-006
) 3h:-00r.
3 9h-0ut.
i. ' ih.Out.
1.7H-i)07
1.5H-i)07
4.SH-i)07
2.2E-007
5 3K-0I);
mg/kg/day
mg'kg/day
mg'kg'day
mg'kg'day
mgkg'day
mg'kg'day
mg'kg'day
mg'kg'day
mg'kg'day
mg'kg''day
mg'kg/day
2.4E-002
5 5 b' oo :
i .ooE-f in:
NA
NA
NA
).7E+i)01
fi.3L-000
l.SE'OOO
4. SOF, i 000
NA
1/mg/kg/day
1/mg/kg/day
1/mg/kg/day
l/mg'kg/day
l/mg'kg/day
1/ing'kgday
l/mg'kg''dyy
l/mg'kg''day
1/mg/kg'day
1/mg/kg/day
)/mg'kg/day
CanrerRi ik
NA
.V.^EOOh
N,\
NA
NA
NA
1.2E-00(i
4E.(}0h
NA
4 2h OOS
NA
NA
NA
NA
1 6E-0(1S
t-E-OOS
5E-0nt.
5E-O0h
?E-006
I'.IEOO?
NA
NA
NA
NA
NA
NA
NA
9.SE-007
:.4E-007
2.7E-00S
NA
NA
N \
2.HE-(tOf.
9.7E-007
S.7E-007
9.t-E-007
NA
Non-L
Intake/Exposure ironcenlrBiion
Value
; .7H-00!
2.hi-. 01)5
2.*.H-iH)4
2.5H-0O1
;.7E-O03
(i.2E-i}0J
9.2 E-01 1
Units
ma'kg'day
mg'kg'day
mgkg'day
mg'kg'day
mg'kg/day
mg'kg'day
mg'kg/day
anrer l lazj i rd Calcu ations
RfD; RIC'
Value
1.0 E* 000
3.(lE-004
3.(i|-:-ii03
3 OK.001
7.OK-00 2
l.OK-003
N/A
Units
mg'kg/day
mg'kg'day
mg'kg 'd jy
mg/kg'day
mg'kg'day
mg'kg/day
mg'kg'day
3 7E-00.(
.' hE-()il7
3 fiK-Odd
3 5h-()03
3 SK-0(15
8 6E-00(i
1 3h:-Oi2
mgkg'day
mgkg'day
mg'kg'day
mg'kg'day
mg/kg'day
mg.'kg/dav
mg/kg/day
LOK-1)110
3.ilE-i')il4
7 5 E-005
3 0H-001
2SK-003
2.6E-004
NA
mg/kg'day
mg/ kg'day
mg'kg'day
mg'kg'day
mg/kg/day
mg/kg/day
mg/kg/day
8.3 K-007
1.91--002
l . lK-003
4,5E-00(^
mg'kg/day
mg/kg/day
mg'kg'day
mg'kg'day
3.0K-004
3.0K-001
7.0K-U02
1 OK-OOl
mg/kg/day
mg/kg/day
mg/kg/day
mg'kg/day
4.7K-004
5.1E-005
3.1E-005
1.5E-0O5
4.5H.0O5
1.2i;-004
1.9E-00^
1.&K-00(^
5.t^E-00f.
2.5H-OOh
ft,]K-001
mg'kg'day
mg'kg/day
mg'kg/day
mg'kg/day
mg'kg'day
mgkg'day
mg'kg/day
mg'kg/day
mg'kg/day
mg'kg/day
mg'kg/day
3.0K-f>02
4 0K00.*
1.0E-()02
3,OK-004
4 0K-1I03
: . O K - O M :
3.OK-00 5
8.OK-1)0 3
2.0E-0U4
5.0E-004
1 OK'000
mg'kg/day
mg/kg/day
mg/kg/day
mg/kg/day
mg'kg/day
mg-kg/day
mg/kg'day
mg/kg'day
mg'kg/day
mg'kg/day
mg/kg/day
Hazard Ouolicnt
0.27
0.09
(LO-*
0.84
0.04
0.62
NA
:
ooon
n 1)012
U.04S
0 012
0014
0 0?
NA
0.1
2
2
0.0028
0.0645
0.0151
0.0045
0 087
OO'J
OO'J
0.09
n.02
0.01
0.003
0.05
0.01
O.OI
0 06
o.ooo:
0 03
001
0 61
TABLE 7.14 RME 2006
CA IXULAT ION OF CHEMICAL CANCER RISKS AND NON-CANCER HAZ.,VRDS
Sigmon's Sepiic Tank
Statesville. Iredell Counlv, North Carolina
Scenari
Recepto
RecepiL
Timeframe: Cuneni/Kuiure
r Population: Resident
rAge: Child
Medium
Groundwater
Exposure
Medium
Exp-Jiure Poini Exp-'surc
Rome
Hip . Route Tula!
Chemical of
Poteniial Concern
^\rsenic
Banum
l ion
Lead
Manganese
Mercury
Vanadium
HPC
Value
O.OiJJ
1.07
5.S
O.OOSh
15.133
0.1 M4
IJ.02J3
Umis
mg/ l .
mg/L
mg/L
mg/L
mg/L
mg'L
mg/L
Exposure Point Toial
Exposure Medium Total
Cioundwaier Groundwater
Tap Waier
Inhalation o fVOCs
while Showenng
Exp. Route Total
1 ,4 -D ichk i iubcn
Benzene
Ch l i j r yConn
Tr ie hlor OCI hone
U.I.1U7-1
l.i.()tl(l74
(J.OOU-IO
u.ooo:4
mg/L
mg'L
mg/L
mg'L
E.ip.)Sijie Point Tola!
K.iposure Medium Total
Groundwaler Tota l
Cancer Risk Calculations
lnl.ikc/K\p<isute Conccnfraiion
Value
2.2K-005
5.9H-003
3.2E-002
4.7E-005
S..fE-002
2.4E-I)0J
1.3H-0(I4
Un i i i
mg'kg/day
mg'kg'day
mg'kg/day
mg'kg/day
mg'kg-'day
mg/kg.'d;iy
mg'kg. day
CES'Uni iRUk
Viilue
l.5EiOO(i
NA
NA
NA
NA
NA
N, \
Lin its
l/mg'kg/day
I/mg/kg/day
i/mg'kg/day
1/mg/kg/day
1/mg/kg/day
l/i i ig'kg'd;iy
l:'mg/kg''day
4.iE-005
4.3E-00^
2 7E-0()^
l.3K-0()6
mg'kg/day
mg'kg/da>-
mgkg'day
mg'kg'day
NA
2.7 K-002
S 1H o o :
NA
l/mg/kg/day
1/mg/kg/day
l/mg'kg/'day
l/mg'kg/'day
Tu ia l f Receptor Risks A c r o i t A l l .Media
Cancer Risk
? ?E-005
NA
NA
NA
NA
NA
NA
4E-il05
4K 005
4E-005
NA
1 K-007
: K - 0 0 7
NA
3E-007
3E-007
3E-0O7
4E-ni')5
4E-005
Non-Cancer l l a / j r d Calculations
Intake/K^poiur
Value
2.6E O04
t..8K-O02
3.7K-001
5.5K-004
9 7E-001
2.^E-0y.^
l.hE-00^
-O incemn i i un
Units
mg'kg'day
mgkg/day
mg/kg/day
mg'kg/day
mg/kg/day
mg'kgday
mg/kg'day
R ID 'RH:
Value
3 OE-OO.:
7 0E0O2
3 0E-001
NA
7 oE-oo:
.VOE 004
l.OE-OO.l
Units
mg'kg/day
mg/kg/day
mg/kg/day
mg'kg/day
mg/kg/da>
tug/kg/da V
mg/kg'day
4.7E-004
5.tE-O05
3.1E-O05
1.5E-O05
mg'kg/day | 2.3E-001
mg'kg/day
mg'kg'day
mg'kg/day
.S.6E 003
NA
1 OE-002
mg'kg/day
mg/kg/day
mg'kg'day
mg/kg'day
Tolnl uf Receptor Hazards Ac i oss A l l Media
Hazard tjuotient
0.^5
0.98
1.2
NA
l l . S
1.4
1.6
2'*
29
29
0.002
O.Odh
NA
0 002
0 001
0.009
0 004
2 i
.M
Scnuiio Timerrame:
Receptor Populaiion:
Rece{>lor Age: Child
Curreail/Future
Residenl
TABLE 7.14 RME REVISED 2009
CALCULATION OF CHEMICAL CANCER RISKS AND NON-CANCER HAZARDS
Sigmon's Septic Tank
Statesville, Iredell County, North Carolina
Medium
Soil/Diy Sedimsfit
Expoaae
Meiktaa Route
Soil/Diy Sedimeni SuifKe Soilrt)ry Sediment Ingestion Orfsiie
Exp. Route Tolal
Dennal
1 Exp. Route Total
Chemical of
Potential CMKeni
Vanadium
HFC
Value
47.95
Unils
mg/lie
Vanadium 47.95 mg/ltg
Expoan-e Point Total
Exposure Medium Total
SolVpry Sediment ToUl
Cucer Risk Calctilaliofls
Imake/Exposuie Concentndon
Vahie
5.3E-0O5
Unils
CF&UnilBUsk
Value
nig;T(&'day NA
Unils
1/mg.lcg/day
../
7.2E.0O7 mg/ltg/day j NA
1
l/m&lg/day
Tolxl ofRKcplor Riiki Acrais .Ul Media
Cancer Risk
NA
NA
N(s|.CaiicerHaaidCalculaliais ||
intake/Exposure Concentration
Value
6,2E-(K)4
Unils
mg/kg/day
RIMMC
Value
5.O(IE.O03
Units
mg.kg/day
- - :
86F..(K)6 mg/kg/day l.iOE-00.3 mg/kg/day
Total of Receptor llaaanli Across AR Media
Hazard Quotient
0.12
0.12
O.OI
0.01
0.13
0.13
0.13
0.13
®
BLACK & VEATCH
Technical Memorandum
To: Beverly Stepter, EPA Remedial Project Manager
From: Mike Profit, Black & Veatch
Re: Human Health Risk Evaluation
Stockpile Samples
Sigmon's Septic Tank Superfund Site
Statesville, Iredell County, North Carolina
Date: June 12,2009
Data obtained from the April 2009 stockpile soil investigation conducted by Science and
Ecosystem Support Division (SESD) was screened according to Environmental
Protection Agency (EPA) Region 4 policies. Chemicals of potential concem (COPCs)
were selected and exposure point concentrations based on the maximum detected
concentration were established. Residential exposure assumptions were applied to the
resultant exposure point concentrations (EPCs).
According to EPA Region 4's policy, the target total individual risk resulting from
exposures at a Superfund site may range anywhere between 1x10" and 1 x IO'* (EPA,
2000). Thus, remedial alternatives should be capable of reducing total potential
carcinogenic risks to levels within this range for individual receptors.
The total estimated cancer risk for the current and future residents (3 x 10'̂ ) is within the
EPA target cancer risk range of 1 x 10" to 1 x 10" . The total hazard index for current and
fiature child residents is 3, which is above the EPA threshold of 1. However, when target
organs are evaluated, none exceeds 1. This indicates that noncancer health effects will
most likely not occur from residential exposures at the site.
OSWER Directive 9355.0-30, issued on April 22, 1991, provides fiirther insight into the
acceptable risk range when it states: "Wliere the cumulative carcinogenic site risk to an
individual based on reasonable maximum exposure for both current and future land use is
less than 1 x lO""*, and the non-carcinogenic hazard quotient is less than 1, action
generally is not warranted unless there are adverse environmental impacts. A risk
manager may also decide that a baseline risk level less than 1 x lO"'* is unacceptable due
to site-specific reasons and that a remedial action is warranted. The upper boundary of
the risk range is not a discrete line at 1 x 10" ,̂ although EPA generally uses 1 x 10""* in
making risk management decisions. A specific risk estimate around 1 x iQ may be
considered acceptable if justified based on site-specific conditions."
EPA, 2000. U.S. Environmental Protection Agency, Supplemental to RAGS: Region 4
Bulletins Human Health Risk Assessment Bulletins, EPA Region 4 Originally Published
in November 1995: httD://www.epa.Qov/reaion4/waste/oftecser/healtbul.htm. 2000.
Table 7.1.RME
CALCULATION OF CHEMICAL CANCER RISKS AND NON-CANCER HAZARDS
REASONABLE MAXIMUM EXPOSURE
Sigmon's Septic Tank Superfund Site
Scenario Timeframe.
Receptor Population:
Receptor Age:
Current/Future
Residenl
Lifetime (cancer), Child (noncancer)
Medium
Soil
Soil
Exposure
Medium
Soil
Soil
Exposure
Point
Stockpile
Stockpile
Exposure
Route
Ingestion
Exp. Route Total
Dermal
Exp. Route Total
Chemical
of Potential
Concern
Aluminum
Antimony
Arsenic
Chromium
Cobalt
Copper
Iron
Manganese
Mercury
Nickel
Thallium
4-Chloroaniline
Benzo(a)Anthracene
Benzo(a)Pyrene
Benzo(b)Fluoranthene
Benzo(k)Fluoranlhene
Chrysene
Dibenzo(a, h)anthracene
lndeno(l ,2,3-cd}PeryIene
EPC
Value
3.9E+04
1.3E+01
3.4E»00
2.2E+02
1.2Et01
4.3E+02
2.6E+04
4.4Et02
I.SEtOO
2.3E+02
7.6E-01
lE+01
1 4E-01
3.2E-01
4 0E-01
1.9E-01
2.0E-01
2.1E-01
6.3E.01
Unils
mg'kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Aluminum
Antimony
Arsenic
Chromium
Cobalt
Copper
Iron
Manganese
Mercury
Nickel
Thallium
4-Chloroaniline
Benzo(a)Anthracene
Benzo(a)Pyrene
Benzo(b}FI uoranthene
Benzo(k)Fluoranthene
Chrysene
Dibenzo(a. h)anthracene
lndeno(l,2,3-cd)Perylene
3.9E+04
1.3E+01
3.4E+00
2.2Et02
1.2E+01
4.3E+02
2.6E+04
4.4E*02
1.3E+00
2.3E»02
7 6E-01
1E+01
1.4E-01
3.2E-01
4.0E-01
1.9E.01
2.0E-01
2.1E.01
6.3E-01
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Intake/ Exposure
Value
6E-02
2E-05
5E-06
3E.04
2E-05
7E-04
4E.02
7E-04
2E-06
4E.04
1E-06
2E-05
2E-07
5E.07
6E-07
3E-07
3E-07
3E-07
1E.06
Cancer
Concentration
Units
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
2E-03
5E-07
1E-07
9E-06
6E-07
2E-05
1E-03
2E.05
5E-08
1E-05
3E-08
5E-06
6E-08
1E-07
2E-07
8E-08
8E-08
9E.08
3E-07
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Risk Calculations
CSF/UnitRisk
Value
NA
NA
1.5E»00
NA
NA
NA
NA
NA
NA
NA
NA
5.4E-02
7.3E-01
7.3E+00
7.3E-01
7.3E-02
7.3E-03
7.3EfOO
7.3E.01
Units
NA
NA
(mg/kg-day)-1
NA
NA
NA
NA
NA
NA
NA
NA
(mg/kg-day)-1
(mg/kg.day).1
(mg/kg-day)-1
(mg/kg-day). 1
(mg/kg-day)-1
(mg/kg-day)-1
(mg/kg-day>-1
(mg/kg-day)-1
NA
NA
5.0E+01
NA
NA
NA
NA
NA
NA
NA
NA
5.4E.02
7.3E-0I
7.3E+00
7.3E-0I
7.3E-02
7.3E.03
7.3EtOO
7.3E.01
NA
NA
(mg/kg-day)-1
NA
NA
NA
NA
NA
NA
NA
NA
(mg/kg-day)-1
(mg/kg-day)-1
(mg/kg-day)-1
(mg/kg-day)-l
(mg/kg-day)-1
(mg/kg-day)-1
(mg/kg.day)-1
(mg/kg-day)-1
Cancer
Risk
NA
NA
8E-06
NA
NA
NA
NA
NA
NA
NA
NA
9E-07
2E-07
4E-06
5E-07
2E-08
2E.09
2E-06
7E-07
2E-05
NA
NA
7E-06
NA
NA
NA
NA
NA
NA
NA
NA
3E-07
4E-08
1E-06
1E-07
6E-09
6E-10
6E-07
2E-07
9E-06
Non.Cancer Hazard Calculations |
Intake/ Exposure
Value
5.0E-01
1.7E-04
4.3E-05
2.8E-03
1.5E-04
5.5E-03
3.3E.01
5.6E-03
1.7E-05
2.9E-03
9.7E-06
1.4E-04
1.8E-06
4.1 E-06
5.1 E-06
2.4 E-06
2.6E-06
2.7E-06
8.1E.06
Concentration
Units
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
7.0E-03
2.3E-06
6.1E-07
3.9E-05
2.1E.06
7.7E-05
4.7E-03
7.9E-05
2.3E-07
4.1 E-05
1.4E-07
2.0E-05
2.5E-07
5.7E.07
7.2E-07
3.4E-07
3.6E-07
3.8E.07
1.1 E-06
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
RfD/RfC
Value
IE+00
4E-04
3E-04
2E+00
3E-04
4E-02
7E.01
1E-01
NA
2E.02
7E-05
4E-03
NA
NA
NA
NA
NA
NA
NA
Units
(mg/kg-day)
(mg/kg-day)
(mg/kg-day)
(mg/kg-day)
(mg/kg-day)
(mg/kg-day)
(mg/kg-day)
(mg/kg-day)
NA
(mg/kg-day)
(mg/kg-day)
(mg/kg-day)
NA
NA
NA
NA
NA
NA
NA
100%
4.0E-04
9.0E-06
3.8E-02
3.0E-04
4.0E-02
7.0E.01
1.4E-01
NA
2.0E-02
6.5E.05
4.0E-03
NA
NA
NA
NA
NA
NA
NA
(mg/kg-day)
(mg/kg-day)
(mg/kg-day)
(mg/kg-day)
(mg/kg.day)
(mg/kg-day)
(mg/kg.day)
(mg/kg-day)
NA
(mg/kg-day)
(mg/kg-day)
(mg/kg-day)
NA
NA
NA
NA
NA
NA
NA
Hazard
Quotient
0.5
0.4
0.1
0.0
0.5
0.1
0.5
0.04
NA
0.1
0.1
0.04
NA
NA
NA
NA
NA
NA
NA
3
0.01
0.01
0.1
0.00
0.01
0.00
0.01
0.00
NA
0.00
0.002093
0.005
NA
NA
NA
NA
NA
NA
NA
0.1
Sigmons Waste Pile Calcs.xls Page 1 of 2
T a b l e / . L R M E
CALCULATION OF CHEMICAL CANCER RISKS AND NON-CANCER HAZARDS
REASONABLE MAXIMUM EXPOSURE
Sigmon's Septic Tank Superfund Site
Scenario Timeframe:
Receplor Population:
Receptor Age:
Current/Future
Resident
Lifetime (cancer), Child (noncancer)
Medium
Soil
Stockpi le Total
Exposure
Medium
Soil
Exposure
Point
Stockpile
Exposure
Route
Inhalation
Inhalation
Exp. Route Total
Exposure Point Total
Chemical
of Potential
Concern
Aluminum
Antimony
Arsenic
Chromium
Cobalt
Copper
Iron
Manganese
Mercuty
Nickel
Thailium
4.Chloroaniline
Benzo(a)Anthracene
Benzo(a)Pyrene
Benzo(b)FI uoranthene
Benzo(k)Fluoranthene
Chrysene
Dibenzo(a. h)anthracene
lndeno(1,2,3-cd)Perylene
EPC
Value
3.9Et04
1.3E+01
3.4E+00
2.2E*02
1.2E+01
4.3E+02
2.6Et04
4.4E+02
1.3E+00
2.3Et02
7.6E-01
1.1E+01
1.4E-01
3.2E-01
4.0E-01
1.9E-01
2.0E-01
2.1E-01
6.3E-01
Unils
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Exposure Medium Total
Intake/ Exposure
Value
4 E-06
1.42166E.09
4E-10
2.40589E-08
1.31231E-09
4.70243E-08
2.84333E-06
4.81179E-08
1.42166E-10
2.51525E-08
8.31127E.1I
1E-09
2E-11
3E-11
4E.11
2E-11
2E-11
2 E - n
7E.11
Cancer
Concentration
Units
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
=!isk Calculations
CSF/Unil Risk
Value
NA
NA
1.5E*0t
2.9E+02
3.2E+0I
NA
NA
NA
NA
NA
NA
NA
3.9E-01
3.9Et00
3.9E-01
3.9E-01
3.9E-02
4.2Et00
3.9E-01
Units
NA
NA
(mg/kg-day)-1
(mg/kg-day). 1
(mg/kg-day)-1
NA
NA
NA
NA
NA
NA
NA
(mg/kg-day )-1
(mg/kg-day)-1
(mg/kg-day). 1
(mg/kg-day)-1
(mg/kg-day )-1
(mg/kg.day )-1
(mg/kg-day )-1
Total of Receplor Risks
Cancer
Risk
NA
NA
6E-09
7E-06
4E-08
NA
NA
NA
NA
NA
NA
NA
6E-12
lE-10
2E-11
8E-12
8E-13
1E.10
3E-11
7 E-06
3E-05
3E-05
3E-05
Non.Cancer Hazard Calculations |
Intake/ Exposure
Value
1.8 E-05
6.1E-09
1.6E-09
1.0E-07
5.6E-09
2.0E-07
1.2E-05
2.1E-07
6 1E-10
1.1E-07
3 6E.10
5.2E-09
6.6E.11
1.5E-10
1.9E-10
8.9E-11
9.4 E-11
9.9E-11
3.0E-10
Concentration
Units
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
RfD/RfC
Value
0%
NA
8.6E-06
2.3E.06
I.7E-06
NA
NA
1.4 E-05
8.6E-05
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Units
(mg/kg.day)
NA
(mg/kg-day)
(mg/kg-day)
(mg/kg-day)
NA
NA
(mg/kg-day)
(mg/kg-day)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Total of Receptor Hazards
Hazard
Quotient
0.01
NA
0.0002
0.05
0.00
NA
NA
0.01
0.00
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.1
3
3
3
Sigmons Waste Pile Calcs.xls Page 2 of 2
Table 9.1.RME SUMMARY OF RECEPTOR RISKS AND HAZARDS FOR COPCs
REASONABLE M/VXIMUM EXPOSURE Sigmon's Septic Tank Superfund Site
Scenario Timeframe: Receptor Population: Receptor:
Current/Future Residenl Lifetime (cancer). Child (noncancer)
Medium
Soil
Exposure Medium
Soil
Exposure Point
Stockpile
Chemical of Poteniial
Concern
Aluminum Antimony Arsenic Chromium Cobalt Copper Iron Manganese Mercury Nickel Thallium 4-Chloroaniline Benzo(a)Anthracene Benzo(a)Pyrene Benzo(b)Fluoranthene Benzo(k)Fluoranlhene Chrysene Dibenzo(a, h)anlhracene lndeno(1.2,3-cd)Perylene
Chemical Total
Ingestion
NA NA
8E-06 NA NA NA NA NA NA NA NA
9E-07 2E-07 4E-06 5E-07 2E-08 2E-09 2E-06 7E-07
2E-05
Carcinogenic Risk
Dermal
NA NA
7E-06 NA NA NA NA NA NA NA NA
3E.07 4E.08 1E.06 1E.07 6E.09 6E-10 6E.07 2E-07
9E-06
Inhalation
NA NA
6E-09 7E-06 4E-08
NA NA NA NA NA NA NA
6E-12 1E-10 2E-11 8E-12 8E-13 1E-10 3E-11
7E-06
Exposure Point Total
Exposure Medium Tolal
Stockpile Total
Receptor Total
Exposure Routes Total
NA NA
2E.05 7E-06 4E-08
NA NA NA NA NA NA
1E-06 2E-07 5E-06 6E-07 3E-08 3E-09 3E-06 9E-07
3E-05
3E-05
3E-05
3E-05
3E-05
Non-Carcinogenic-Hazard Quotient
Primary Target Organ(s)
CNS Blood Skin NA NA NA
Gl Tract/Liver CNS NA
Decreased body and organ weights Liver
Spleen NA NA NA NA NA NA NA
Ingestion
0.5 0.4 0.1 0.0 0.5 0.1 0.5 0.0 NA 0.1 0.1
0.04 NA NA NA NA NA NA NA
3
Dermal
0.01 0.0 0.1
0.001 0.01 0.002 0.01
0.001 NA
0.002 0.002 0.005
NA NA NA NA NA NA NA
0.1
Inhalation
0.01 NA
0.0002 0.05
0.003 NA NA
0.01 0.00001
NA NA NA NA NA NA NA NA NA NA
0.1
Exposure Routes Total
0.5 0.4 0.2
0.05 0.5 0.1 0.5 0.1
0.00001 0.1 0.2
0.04 NA NA NA NA NA NA NA
3
3
3
3
3
Tola! Incremental Risk = | 3E-Q5 Total Hazard Index =
Total CNS Hazard Index =
Total Liver Hazard Index =
Total Gl Trad Hazard Index =
Total Blood Hazard Index =
0.6
Sigmons Waste Pile Calcs.xls Page 1 of 1 7/31/2009
APPENDIX C
Summary of Cost Estimate for the Stockpile
IGCE - Detailed Remedy Cost Estimates
(Stockpiles) Excavation, Off-site Transportation, and Disposal at Approved Landfill
Site Name: Sigmon's Septic Tank Site Site Location: Statesville, North Carolina
Item Description
MOBILIZATION/ DEMOBILIZATION Transport Equipment & Staff Temporary Facilities
EXCAVATION Soil Excavation
Grading & Compacting Seed & Mulch
OFF-SITE LANDFILLING Truck Transport
Disposal at Landfill
EQUIPMENT & MATERIALS Health & Safety Equipment
Units
each each
cy
acre acre
Truck-load ton
each Subtotal Capital Cost Fuel & Administrative Cost Equipment & Supplies $52,000 - Eq. Analytical Laboratory (Dispose Paramete Labor - $70,000, (Lodqinq & per diem - $33
Quantity
1 1
4,100
1.0 1.0
195
4,100
1
[Supplies-rs) 000, travi
PRESENT WORTH COST
Discount Rate: 7%
Unit Price
Dollars
$40,000 $10,000
$10
$5,000 $2,000
$700
$65
$10,000
$20,000)
3l - $8800
Total Cost Dollars
$40,000 $10,000
$41,000
$5,000 $2,000
$136,500
$266,500
$10,000 $511,000 $10,000 $72,000 $20,000
$111,800
TOTAL PRESENT WORTH COST Contingency (25% of Subtotal) $181,2 00
$724,800 $906,000
APPENDIX D
Responsiveness Summary
No Comments Were Received
